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Ann Thorac Surg 2006;81:1162-1171
© 2006 The Society of Thoracic Surgeons
Department of Cardiac Surgery, Royal Hospital for Sick Children, Glasgow, United Kingdom
* Address correspondence to Dr Raja, Department of Cardiac Surgery, Royal Hospital for Sick Children, Yorkhill NHS Trust, Dalnair St, Glasgow G3 8SJ, United Kingdom (Email: drrajashahzad{at}hotmail.com).
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Abstract |
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Introduction |
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Some 250,000 patients experience in-stent restenotic lesions each year worldwide [10]. In-stent restenosis has been recognized as very difficult to manage, with a repeat restenosis rate of 50%, regardless of the angioplasty device used [10]. Despite an exhaustive search for an effective pharmacotherapy to treat or prevent restenosis, hundreds of clinical trials have failed to identify a pharmacologic agent with proven therapeutic benefit [11]. Experience with systemically administered drugs, such as antiplatelet agents, anticoagulants, calcium-channel blockers, angiotensin-converting enzyme inhibitors, cholesterol-lowering agents, and antioxidants, has proven almost universally negative [12]. Similarly, the results with oral administration of an antiproliferative agent, sirolimus, have failed to show any benefit, and in fact there was a higher incidence of adverse events in the recipients of such a therapy [12]. Vascular brachytherapy over the years, by convincingly reducing the incidence of repeat in-stent restenosis (by 50%), has emerged as the gold standard of therapy [10]. However, larger studies and long-term follow-up showed alarming long-term sequelae such as edge restenosis and late thrombosis, raising some concerns about the potential toxicity of a cytotoxic approach [13].
The recent introduction of drug-eluting stents (DES) in clinical practice has shown a great deal of promise for the treatment of both de novo and restenotic lesions, with reduction in in-stent neointimal proliferation that causes restenosis, thereby reducing the incidence of symptomatic recurrence to less than 5%, rivaling that of bypass surgery [14]. Since Food and Drug Administration (FDA) approval of the first DES in April 2003, referrals for stenting have increased by more than 40%, and correspondingly, bypass surgery rates have begun to decline [15]. The early encouraging results and less invasive nature of DES coupled with the trauma involved in surgical access ("cracking the chest") and conduit harvest, the systemic inflammatory response associated with cardiopulmonary bypass, the threat of postoperative neurocognitive dysfunction, and vein graft attrition has resulted in many physicians going to great lengths to avoid recommending surgical revascularization to their patients [16].
Despite enthusiastic speculation of the interventionalists that probably CABG will soon become a relic of the past, reality is that valid concerns exist regarding long-term efficacy of DES [17]. Furthermore important safety issues such as thrombosis, late stent malapposition, aneurysm formation, edge effect, late inflammation due to choice of polymer used to bind the drug, the release of toxins, and potential interaction with brachytherapy have not yet been completely addressed [18]. This review article evaluates current status of DES with special emphasis on real and potential drawbacks of this emerging PCI modality and its impact on the practice of coronary artery bypass surgery.
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Short-Term and Midterm Outcomes of DES |
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 TopAbstractIntroduction Short-Term and Midterm Outcomes... Impact of DES on...Potential Drawbacks, Concerns,...Implications of Increasing DES...Hybrid Revascularization--The...ConclusionsReferences |
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Material and Methods
A search of Medline, Embase, Cochrane Controlled Trials Register, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Science Citation Index, Current Contents, NHS Economic Evaluation Database, and International Network of Agencies for Health Technology Assessment databases from the date of their inception to the last week of May 2005 using medical subject headings search terms "randomized controlled trials," "meta-analysis," "stents," and nonmedical subject headings search terms "drug-eluting stents," "sirolimus," and "paclitaxel" yielded a total of 11 randomized controlled trials comparing DES and bare metal stents, recruiting 5,287 patients (2,731 allocated to DES, and 2,556 to bare metal stents) and reporting at least one pertinent clinical, radiologic, or economic outcome with at least 6 months of follow-up. These included the following: RAVEL (RAndomized study with sirolimus-coated Bx VELocity balloon-expandable stent in the treatment of patients with de novo native coronary artery lesions) [22]; SIRIUS (SIRolImUS-eluting balloon-expandable stent in the treatment of patients with de novo native coronary artery lesions) [23]; E-SIRIUS (European multicenter randomized double-blind study of the SIRolImUS-eluting balloon-expandable stent in the treatment of patients with de novo native coronary artery lesions) [24]; C-SIRIUS (Canadian multicenter randomized double-blind study of the SIRolImUS-Eluting balloon-expandable stent in the treatment of patients with de novo native coronary artery lesionsS) [25]; SES-SMART (Sirolimus-Eluting Stent in the prevention of restenosis in SMall coronary ARTeries) [26]; TAXUS (Treatment of de novo coronary disease using a single pAclitaXel elUting Stent)–I, –II, and –IV [27–29]; ELUTES (European evaLUation of pacliTaxel-Eluting Stent) [30]; ASPECT (ASian Paclitaxel-Eluting stent Clinical Trial) [31]; and DELIVER (Drug-ELuting coronary stent system In the treatment of patients with de noVo nativE coronaRy lesions) [32]. A 3-year follow-up of the RAVEL trial has also been published recently, suggesting maintenance of long-term clinical benefits [33]. In addition the TAXi (Paclitaxel and sirolimus stents in the real world of interventional cardiology) trial [34], comparing SES with PES, and seven meta-analyses [35–41] as well as three systematic reviews [42–44] of clinical trials of SES and PES in patients with obstructive coronary artery disease have also been published.
Randomized Controlled Trials of DES
Analysis of all published randomized controlled trials comparing SES or PES with bare metal stents shows that in general, the patients enrolled in the trials of DES with sirolimus or paclitaxel were young and predominantly male. The trials were well conducted, with random allocation of treatment, masking of treatment assignment in most trials, and clinical follow-up rates of more than 90% (Table 1). Follow-up quantitative coronary angiography was done in 43% to 97% of enrolled patients 6 to 9 months after the index percutaneous coronary intervention with intravascular ultrasound done in 17% to 100% patients in 7 of the 11 randomized controlled trials (Table 1). Most trials were designed to assess the medium-term (6 to 12 months after index percutaneous coronary intervention) efficacy of DES at decreasing angiographic restenosis or clinical events. The inclusion criteria of all the trials specified that enrolled patients had de-novo (not restenotic) lesions in a native coronary artery with the exception of TAXUS I trial. Multilesion percutaneous coronary intervention with DES was not permitted in any trial. Patients with a recent myocardial infarction or a low ejection fraction were also excluded. Prevalence of diabetes ranged from 14% to 31%. Lesion lengths and reference-vessel diameters of the treated vessels varied between the trials, although in general the stented lesions were intermediate in length in medium-caliber vessels (Table 2). Depending on the study protocol, aspirin was given to all patients indefinitely and antiplatelet therapy with clopidogrel [22–30, 32], ticlopidine [24], or cilostazol [31] was recommended for at least 2 to 6 months after percutaneous coronary intervention. The use of glycoprotein IIb/IIIa inhibitors ranged from 0% to 64%. Glycoprotein IIb/IIIa inhibitors were used at the operator's discretion in most studies [22–26, 28–30], although in some of them these were either not used or discouraged [27, 31, 32].
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The TAXi trial [34] is the only trial to date that recruited patients representing real world interventional cardiology practice to evaluate whether a PES or an SES is superior in daily practice. A total of 202 patients were included in this trial. One hundred patients received a PES and 102 received an SES. Procedural success was 99% in both groups. Incidence of major adverse cardiac events at follow-up (mean, 7 ± 2 months) was 4% with the PES and 6% with the SES (p = 0.8). The need for target lesion revascularization was very low in both groups (1% with the PES and 3% with the SES), confirming that the high success rate obtained with both stents in randomized trials can be replicated in routine clinical practice. However, owing to the small sample size, this trial was unable to show any advantage of one stent over the other.
Registries and "Real World Practice" of DES
Clinical trials are conducted under controlled conditions with strict inclusion and exclusion criteria, and their results may not be translated into "real world" clinical practice where indications of use of these DES are more liberal. After the commercial availability of DES in Europe and the United States, several single and multicenter registries were initiated aiming to scrutinize the utilization of DES for the treatment of more challenging lesions and various patient subsets.
The findings from RESEARCH (Rapamycin Eluting Stent Evaluated At Rotterdam Cardiology Hospital) registry—the first large-scale registry of unrestricted use of SES—extend our knowledge about the clinical efficacy of SES in complex patient subsets. Approximately 68% of patients included in the registry would have been excluded from the earlier clinical trials (eg, patients with previous coronary surgery, patients admitted with acute myocardial infarction, and those with multivessel stenting, among other high-risk characteristics). A 1-year follow-up comparative analysis of consecutive patients with de novo lesions (n = 508) treated exclusively with SES and 450 patients who received bare stents in the period just before the introduction of DES revealed that patients in the SES group more frequently had multivessel disease, more type C lesions, received more stents, and had more bifurcation stenting [45]. At 1 year, the cumulative rate of major adverse cardiac events (death, myocardial infarction, or target vessel revascularization) was 9.7% in the SES group and 14.8% in the pre-SES group (hazard ratio [HR], 0.62, 95% confidence interval [CI]: 0.44 to 0.89; p = 0.008). The 1-year risk of clinically driven target vessel revascularization in the SES group and in the pre-SES group was 3.7% versus 10.9%, respectively (HR, 0.35, 95% CI: 0.21 to 0.57; p < 0.001).
In three separate reports, RESEARCH investigators have shown DES implantation as highly effective for focal in-stent restenosis [46] and a promising and safe strategy for left main coronary artery lesions [47] and for patients with ST-elevation acute myocardial infarction [48]. More importantly, RESEARCH registry provides unique insights into the technical aspects of stent deployment techniques. Implantation of SES was always performed at high pressures (more than 12 atmospheres), and postdilatation was liberally performed to achieve optimum angiographic results. Care was taken to avoid vessel injury beyond the stented area, and postdilatation was performed with balloons shorter than the stent length. The number of stents, the total stented length, and the utilization of longer stents were higher in the SES group than in the bare stent group, which reflects an attempt of the operators to avoid geographical miss and cover the entire diseased segment with the DES (ie, "from normal tissue to normal tissue")—the "longer is better" philosophy. However, whether the low incidence of acute complications and the low rate of long-term adverse events were influenced by the procedural strategy applied in the RESEARCH registry remains to be clarified and warrants further investigation.
Another multinational postmarketing surveillance registry, e-CYPHER, is designed to determine safety and reliability of SES use in routine, worldwide daily practice. This Internet-based registry will enroll 15,000 patients from 417 sites worldwide. All patients receiving at least 1 SES are enrolled, and both on- and off-label use are recorded. One-, 6-, and 12-month clinical follow-up will be performed without mandatory angiographic follow-up [49,50]. One-year results of the 4,926 patients including multiple lesions (26%), ostial (8.4%), left main (2.2%), chronic total occlusion (8.9%), bifurcation (8.6%), long lesions greater than 30 mm (12.2%), restenosis (13.1%), vein grafts (2.1%) and complex B2 or C lesions (86.6%) appear encouraging. The rates of acute complications with SES implanted in unselected patients worldwide were at least similar to those seen with bare metal stents, and did not differ from rates reported in previous randomized clinical trials. The overall major adverse cardiac event rate at 6 months was 5.8% (death = 2.1%, myocardial infarction = 1.4%, target lesion revascularization = 2.3%) [51].
Very encouraging preliminary results also come from the "real world" data on TAXUS SR stent collected in the WISDOM Registry (Web-based TAXUS Intercontinental obServational Data TransitiOnal registry prograM) and in the Real Life PBPaclitaxel Registry (Real Life Polymer-Based Paclitaxel Registry) [52], the German Cypher Registry [53], and the Milan Complex Lesion Registry [54].
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Impact of DES on Volume of Coronary Artery Bypass Surgery |
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In the present era of "DES euphoria" where the motto is "just DES it!" enthusiastic interventionalists in frenzy do not hesitate in making suggestions that "DES will put the bypass surgeons out of business" [15] and that cardiothoracic surgeons of the world should "get a new day job!". However, an unbiased analysis of the situation at present clearly suggests that such claims are premature and not backed by solid scientific and clinical evidence. In fact, at present nothing is known about the long-term outcome with these devices compared to surgery. To date, results of only one randomized controlled trial comparing DES with minimally invasive direct coronary artery bypass graft surgery (MIDCABG) in patients with left anterior descending coronary artery (LAD) stenosis have been published [55]. In this trial symptomatic patients (n = 189), with an isolated high-grade lesion (stenosis of 
70% of the luminal diameter) in the proximal LAD coronary artery (from the ostium to the first diagonal branch), were randomly assigned to the DES group (n = 119) and the MIDCABG group (n = 70). During the 6-month follow-up period, 1.7% (n = 2) in the DES group needed repeated revascularization procedures for target lesion revascularization compared with 5.9% (n = 4) in the MIDCABG group (p = 0.196). The rates of death and myocardial infarction were similar in both groups (DES 0.0% [n = 0] versus MIDCABG 2.9% [n = 2], p = 0.135; DES 1.7% [n = 2] versus MIDCABG 2.9% [n = 2], p = 0.627; respectively) during 6 months of follow-up. In-hospital length of stay was significantly shorter in the DES group compared with the MIDCABG group (5.8 ± 2.1 days versus 8.9 ± 2.6 days; p = 0.001). Implantation of DES and MIDCABG surgery showed similar rates of myocardial infarction, the need for repeated revascularization, and death during 6 months of follow-up. However, DES implantation resulted in lower average number of hospital stays and similar postoperative complications.
It is expected that the ARTS II study designed to assess the efficacy of the SES in patients (n = 607) with multivessel coronary artery disease compared with those of the surgical (n = 605) and PCI (n = 600) arms of the ARTS I study, as measured by major adverse cardiac and cerebrovascular event-free survival at 1 year, will provide a better comparison of DES and CABG [56]. In addition, the FREEDOM (Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease) trial is an international, multicenter ongoing trial that randomly assigned 2,400 patients with multivessel coronary disease and diabetes mellitus to bypass surgery or SES implantation. The patients will be followed up for 5 years. The SYNTAX (SYNergy Between PCI with TAXUS and Cardiac Surgery) study has been designed to randomize approximately 1,500 patients with three-vessel disease or left main disease, or both, to bypass surgery or multivessel PCI with the TAXUS stent. A parallel registry for patients not enrolled is also planned for both studies. Hopefully, these trials will provide important information to guide the choice of the optimal revascularization strategy for patients with multivessel disease [56]. More importantly, for those with misguided euphoria, the message at present will be that without a strong surgical program, there can be no stent program. Interventional cardiologists who jokingly claim they "want to put their bypass surgeons out of business" may be very sorry if they get what they ask for [15].
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Potential Drawbacks, Concerns, and Unresolved Issues Related to DES |
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TopAbstractIntroductionShort-Term and Midterm Outcomes...Impact of DES on...Potential Drawbacks, Concerns,...Implications of Increasing DES...Hybrid Revascularization--The...ConclusionsReferences |
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Moreover, even the efficacious stents such as the sirolimus-coated stent have been plagued by restenosis. In the SIRIUS trial, the postsirolimus restenosis was significantly increased in diabetes, long lesions, and small vessels [56]. This post-DES restenosis has been shown to frequently occur in association with higher complexity characteristics, which might be responsible for local trauma outside the stented segment, incomplete lesion coverage, uneven distribution of drug release because of asymmetrical stent expansion, or damage of the stent coating [60]. Such observations have prompted investigators to examine methods of improving stent deployment technique. A valid concern is that major changes in the application of stents may occur without waiting for the data to support them. In the attempt to reduce restenosis further to near zero, it is most important to consider safety issues first [61]. Whereas restenosis has not been shown to be the major contributor to survival [62], the complications of acute vessel closure, however, markedly reduce the long-term survival of patients. Therefore, any efforts to control restenosis, by modifying stent deployment techniques, must be balanced by an avoidance of any increase in complication rates.
Stent Thrombosis
Initial uncontained euphoria about DES has been tempered by concerns about an increased risk of stent thrombosis with DES. Owing to the possibility of delayed endothelialization and enhanced platelet aggregation after DES implantation [63, 64], a higher risk of stent thrombosis cannot be excluded. The public was first made aware of subacute thrombosis concerns in July 2003 when Cordis, in conjunction with the FDA, sent a warning letter to physicians reporting that it had received 47 medical device reports of subacute thrombosis after Cypher stent implantation. An official warning letter was subsequently issued on October 29, 2003, by the FDA, in which the agency reported that the number of medical device reports had grown to more than 290 reports (more than 260 reports in the United States and more than 25 reports outside the country) [65]. In a large cohort of 2,229 consecutive patients undergoing DES implantation, Iakovou and colleagues [66] noted a 9-month cumulative stent thrombosis incidence of 1.3%, substantially higher than rates reported in major clinical trials (0.4% at 1 year for sirolimus and 0.6% at 9 months for paclitaxel) [23, 29]. In this study, 27% of the population had diabetes and 79% of the lesions were complex. The clinical consequences of stent thrombosis were severe, with a case-fatality rate of 45%.
This issue has been recently addressed by two meta-analyses of randomized controlled trials comparing bare metal stents with DES [67, 68]. Bavry and coworkers [67] in their meta-analysis on eight trials (total of 13 study arms) in 3,817 patients with coronary artery disease who were randomized to either PES or bare metal stents concluded that compared with bare metal stents, PES do not increase the hazard for thrombosis up to 12 months (risk ratio [RR] = 1.06, 95% CI: 0.55 to 2.04, p = 0.86]). Similar results were obtained when the analysis was restricted to trials with a polymeric stent platform TAXUS-I, –II, –IV, and –VI [RR = 1.01, 95% CI: 0.40 to 2.53, p = 0.99]), trials with longer lesions (TAXUS–IV and –VI [RR = 0.62, 95% CI: 0.2 to 1.91, p = 0.41]), and trials that used a higher dose of paclitaxel (ASPECT, ELUTES, and DELIVER-I [RR = 1.87, 95% CI: 0.52 to 6.81, p = 0.34]). In the other meta-analysis, 10 randomized studies comparing DES and bare metal stents with overall 5,030 patients were included (2,602 were allocated to DES and 2,428 to bare metal stents) [68]. This meta-analysis also concluded that the incidence of stent thrombosis was not increased in patients receiving DES (0.58% versus 0.54% for bare metal stents; odds ratio = 1.05, 95% CI: 0.51 to 2.15; p = 1.000). The overall rate of stent thrombosis did not differ significantly between patients receiving sirolimus- or paclitaxel-eluting stents (0.57% versus 0.58%; p = 1.000). Despite encouraging results from these meta-analyses, one must not forget that most of the randomized controlled trials in these meta-analyses recruited low risk patients who received antiplatelet therapy for 2 to 6 months after PCI. Furthermore, follow-up was limited to 12 months in most trials; therefore, the possibility of very late stent thrombosis after DES implantation cannot be ruled out at present. Although prolonged antiplatelet therapy for as long as 1 year has been proposed as a safeguard against stent thrombosis due to delayed strut endothelialization [69], stent underexpansion (75%), incomplete apposition (33%), and edge dissection (17%) as possible mechanisms for DES thrombosis [70] also need to be tackled to completely eradicate stent thrombosis.
Other Concerns
Synthetic polymers are often used as carriers for the antirestenosis agents, and polymer biocompatibility remains a concern, as polymers often induce an exaggerated inflammatory reaction [71]. Histologic studies show that while initially the polymer stays intact and does not evoke any form of neointimal hyperplasia, as time passes, the polymer begins to degrade and leads to delayed intimal hyperplasia [72]. Furthermore, hydrophobicity of many of the synthetic carrier polymers means that the tissue uptake of drug is 100 times greater than circulating levels [73]. In studies performed on rabbits using chondroitin sulfate and paclitaxel-coated stents, significant medial necrosis and persistent local fibrin deposition occurred, suggesting delayed healing [63]. Although it can be argued that animal and human arteries heal differently, one must reiterate the point that the present human studies have not involved a long enough follow-up period to rule out the eventual occurrence of delayed intimal hyperplasia. Moreover, at present very few human DES pathological studies are available. It is possible that all that is being achieved with the DES systems is a delay in healing, and that the vessel "can only heal one way—by neointimal formation."
Reports of localized [74] hypersensitivity leading to late stent thrombosis as well as systemic hypersensitivity [65] to DES have also surfaced. Localized hypersensitivity to DES has been attributed to nonerodable polymer as similar findings have been observed in the arterial walls of pig coronary arteries [74]. There is a likely spectrum of allergic responses to DES in sensitive patients, varying from benign reactions to excessive inflammation with medial destruction, stent malapposition, and aneurysm formation with late in-stent thrombosis. The enhanced surveillance of patients with DES for late complications along with the development of tests to prescreen patients with potential reactions to polymers may help avoid some of the late-term complications with DES. Continued efforts to improve polymer biocompatibility are warranted [74].
Apart from these concerns, crucial data of larger cohorts are either still missing or limited in some very important subsets, such as in the setting of long lesions, small vessels, acute myocardial infarction, chronic occlusion, multivessel disease, bifurcation lesions, main-stem lesions, in-stent restenosis, diabetic patients, and saphenous vein graft lesions [17, 18]. Despite the significant advances in DES technology, catheter-based interventions in general have not proven well suited to patients with a large atherosclerotic burden, diffuse disease, especially those with small vessels, patients with left main lesions, binary stenoses, evolving myocardial infarction, ostial lesions, severely calcified or thrombotic lesions, or ejection fractions below 25% [16]. Furthermore, in cases of chronic total occlusion, DES may reduce somewhat the high incidence of restenosis, but many of these lesions simply cannot be crossed with a wire, making DES an improbable option. For insulin-dependent diabetic patients, DES have not yet reduced the rate of repeat revascularization. In the SIRIUS trial [23], diabetic DES recipients had a 6.9% repeat revascularization rate just 9 months after stent placement, which is in stark contrast to the much lower repeat revascularization rates of 8.8% after 5 years reported for CABG patients with diabetes [75]. New technology may improve stenting outcomes for these challenging groups, but this has yet to be demonstrated. Finally, there are legitimate concerns about highly undesirable, irreversible toxic effects of high concentrations of drug delivered locally by coating a stent, and the question of how to tackle the initial higher cost of this new technology remains unanswered at present [18], although it is expected that competitions in the market will eventually bring down the initial cost.
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Implications of Increasing DES Placement Volume for Cardiac Surgeons |
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TopAbstractIntroductionShort-Term and Midterm Outcomes...Impact of DES on...Potential Drawbacks, Concerns,...Implications of Increasing DES...Hybrid Revascularization--The...ConclusionsReferences |
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Furthermore, cardiac surgeons must be aware of the potential risk of increased postoperative bleeding in this high-risk group of patients all of whom receive anticoagulation medication before PCI. Modification of surgical techniques such as avoiding cardiopulmonary bypass and performing myocardial revascularization off-pump in patients who have received anticoagulants such as clopidogrel may theoretically reduce the incidence of postoperative bleeding [77] and reduce the morbidity associated with need for reexploration and transfusion of blood products.
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Hybrid Revascularization—The Best Way Forward |
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TopAbstractIntroductionShort-Term and Midterm Outcomes...Impact of DES on...Potential Drawbacks, Concerns,...Implications of Increasing DES...Hybrid Revascularization--The...ConclusionsReferences |
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In these rapidly changing times of catheter-based coronary interventions perhaps integrated ("hybrid") coronary revascularization of patients with multivessel coronary artery disease may be the best way forward. This approach is believed to offer the best of both worlds, MIDCABG and DES, and to optimize acute and long-term clinical outcome. Using MIDCABG will diminish noncardiac complications associated with classical CABG and provide "gold standard" LIMA-to-LAD grafting while DES use will minimize major adverse cardiac events in the long term. Evidence is emerging that restenosis rates after catheter-based interventions on the circumflex and right coronary artery territories are lower than restenosis rates after interventions on the LAD [91]. Recent data have shown that radial artery graft 1- and 4-year failure rates are 4% and 11% [92], and 9-month target vessel reintervention rates in non-LAD targets in the SIRIUS trial reached 3.4% [23], results that suggest that catheter-based intervention using DES on non-LAD lesions are as good as arterial grafts. Furthermore, there is the possibility to carry out catheter-based intervention on non-LAD territories under full protection of a LIMA-to-LAD graft.
The skeptics are likely to say that how can such an approach be adopted without validation by randomized controlled trials. There is no denying that we are currently practicing in an era of evidence-based medicine where double-blinded randomized controlled trials have been allotted the highest level of evidence [93]; however, at the same time, it is extremely important to realize that randomized controlled trials of impractical sizes with extremely long follow-up will be required to conclusively prove the superiority of any myocardial revascularization strategy or technique. Furthermore, such studies are unlikely to be performed because the rate of technological advancement is likely to make the results of such a trial obsolete.
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Conclusions |
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References |
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  G. Yi, Y.-N. Youn, K.-J. Yoo, and Y.-S. Hong Comparison of Off-pump Coronary Artery Bypass Grafting With Percutaneous Coronary Intervention Versus Drug-Eluting Stents for Three-Vessel Coronary Artery Disease Ann. Thorac. Surg., November 1, 2008; 86(5): 1438 - 1443. [Abstract] [Full Text] [PDF]
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